apply simple comments

core/src/main/java/org/elasticsearch/cluster/routing/allocation/allocator/BalancedShardsAllocator.java

@@ -87,18 +87,17 @@ public class BalancedShardsAllocator extends AbstractComponent implements Shards
     @Inject
     public BalancedShardsAllocator(Settings settings, ClusterSettings clusterSettings) {
         super(settings);
-        weightFunction = new WeightFunction(INDEX_BALANCE_FACTOR_SETTING.get(settings), SHARD_BALANCE_FACTOR_SETTING.get(settings));
+        setWeightFunction(INDEX_BALANCE_FACTOR_SETTING.get(settings), SHARD_BALANCE_FACTOR_SETTING.get(settings));
         setThreshold(THRESHOLD_SETTING.get(settings));
         clusterSettings.addSettingsUpdateConsumer(INDEX_BALANCE_FACTOR_SETTING, SHARD_BALANCE_FACTOR_SETTING, this::setWeightFunction);
         clusterSettings.addSettingsUpdateConsumer(THRESHOLD_SETTING, this::setThreshold);
     }
 
-    public void setWeightFunction(float indexBalance, float shardBalanceFactor) {
+    private void setWeightFunction(float indexBalance, float shardBalanceFactor) {
         weightFunction = new WeightFunction(indexBalance, shardBalanceFactor);
     }
 
-
+    private void setThreshold(float threshold) {
-    public void setThreshold(float threshold) {
         this.threshold = threshold;
     }
 

core/src/main/java/org/elasticsearch/common/settings/AbstractScopedSettings.java

@@ -128,22 +128,6 @@ public abstract class AbstractScopedSettings extends AbstractComponent {
                 }
             }
         }
-
-        try {
-            for (Map.Entry<String, String> entry : newSettings.getAsMap().entrySet()) {
-                if (entry.getKey().startsWith("logger.")) {
-                    String component = entry.getKey().substring("logger.".length());
-                    if ("_root".equals(component)) {
-                        ESLoggerFactory.getRootLogger().setLevel(entry.getValue());
-                    } else {
-                        ESLoggerFactory.getLogger(component).setLevel(entry.getValue());
-                    }
-                }
-            }
-        } catch (Exception e) {
-            logger.warn("failed to refresh settings for [{}]", e, "logger");
-        }
-
         return lastSettingsApplied = newSettings;
     }
 

core/src/main/java/org/elasticsearch/common/settings/ClusterSettings.java

@@ -26,6 +26,7 @@ import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.routing.allocation.allocator.BalancedShardsAllocator;
 import org.elasticsearch.cluster.routing.allocation.decider.*;
 import org.elasticsearch.cluster.service.InternalClusterService;
+import org.elasticsearch.common.logging.ESLoggerFactory;
 import org.elasticsearch.discovery.DiscoverySettings;
 import org.elasticsearch.discovery.zen.ZenDiscovery;
 import org.elasticsearch.discovery.zen.elect.ElectMasterService;
@@ -48,6 +49,27 @@ public final class ClusterSettings extends AbstractScopedSettings {
         super(settings, settingsSet, Setting.Scope.CLUSTER);
     }
 
+
+    @Override
+    public synchronized Settings applySettings(Settings newSettings) {
+        Settings settings = super.applySettings(newSettings);
+        try {
+            for (Map.Entry<String, String> entry : settings.getAsMap().entrySet()) {
+                if (entry.getKey().startsWith("logger.")) {
+                    String component = entry.getKey().substring("logger.".length());
+                    if ("_root".equals(component)) {
+                        ESLoggerFactory.getRootLogger().setLevel(entry.getValue());
+                    } else {
+                        ESLoggerFactory.getLogger(component).setLevel(entry.getValue());
+                    }
+                }
+            }
+        } catch (Exception e) {
+            logger.warn("failed to refresh settings for [{}]", e, "logger");
+        }
+        return settings;
+    }
+
     /**
      * Returns <code>true</code> if the settings is a logger setting.
      */

core/src/main/java/org/elasticsearch/common/settings/Setting.java

@@ -45,6 +45,7 @@ public class Setting<T> extends ToXContentToBytes {
     private final Scope scope;
 
     public Setting(String key, Function<Settings, String> defaultValue, Function<String, T> parser, boolean dynamic, Scope scope) {
+        assert parser.apply(defaultValue.apply(Settings.EMPTY)) != null || this.isGroupSetting(): "parser returned null";
         this.key = key;
         this.defaultValue = defaultValue;
         this.parser = parser;

core/src/main/java/org/elasticsearch/discovery/DiscoverySettings.java

@@ -36,6 +36,9 @@ import java.util.EnumSet;
  */
 public class DiscoverySettings extends AbstractComponent {
 
+    public final static int NO_MASTER_BLOCK_ID = 2;
+    public final static ClusterBlock NO_MASTER_BLOCK_ALL = new ClusterBlock(NO_MASTER_BLOCK_ID, "no master", true, true, RestStatus.SERVICE_UNAVAILABLE, ClusterBlockLevel.ALL);
+    public final static ClusterBlock NO_MASTER_BLOCK_WRITES = new ClusterBlock(NO_MASTER_BLOCK_ID, "no master", true, false, RestStatus.SERVICE_UNAVAILABLE, EnumSet.of(ClusterBlockLevel.WRITE, ClusterBlockLevel.METADATA_WRITE));
     /**
      * sets the timeout for a complete publishing cycle, including both sending and committing. the master
      * will continute to process the next cluster state update after this time has elapsed
@@ -50,11 +53,6 @@ public class DiscoverySettings extends AbstractComponent {
     public static final Setting<ClusterBlock> NO_MASTER_BLOCK_SETTING = new Setting<>("discovery.zen.no_master_block", "write", DiscoverySettings::parseNoMasterBlock, true, Setting.Scope.CLUSTER);
     public static final Setting<Boolean> PUBLISH_DIFF_ENABLE_SETTING = Setting.boolSetting("discovery.zen.publish_diff.enable", true, true, Setting.Scope.CLUSTER);
 
-    public final static int NO_MASTER_BLOCK_ID = 2;
-
-    public final static ClusterBlock NO_MASTER_BLOCK_ALL = new ClusterBlock(NO_MASTER_BLOCK_ID, "no master", true, true, RestStatus.SERVICE_UNAVAILABLE, ClusterBlockLevel.ALL);
-    public final static ClusterBlock NO_MASTER_BLOCK_WRITES = new ClusterBlock(NO_MASTER_BLOCK_ID, "no master", true, false, RestStatus.SERVICE_UNAVAILABLE, EnumSet.of(ClusterBlockLevel.WRITE, ClusterBlockLevel.METADATA_WRITE));
-
     private volatile ClusterBlock noMasterBlock;
     private volatile TimeValue publishTimeout;